Answer:
1. a decline - The overall trend of the ice surface has been a constant decline, with approximately a third part less ice since 1978.
2. Why is sea ice melting so much and so fast - The Earth's climate is a complex interconnected system. Thus, it is difficult to determine the exact causes for the ice melt in the Arctic Ocean.
3. ocean salinity will decrease - The ice in the Arctic Ocean is mainly composed of fresh water. Thus, if all of it were to melt, the ocean salinity will decrease considerably and thus affect the global ocean currents.
Step-by-step explanation: